The Spellbinding, Though Misnamed, Lightning Bug Is Much More Than Just a Pretty Light Show

Wonderful West Virginia Magazine

Lantern Beetles The spellbinding, though misnamed, lightning bug is much more than just a pretty light show.

WRITTEN BY PAM KASEY

When night descends, fireflies surround one of the old World War II munitions storage bunkers found at the McClintock Wildlife Management Area near Point Pleasant. JESSE THORNTON JESSE Wonderful West Virginia Magazine

hen it comes Making Light to childhood Before we talk about insect flirtation, it’s useful to high-summer fun, understand that what we call lightning bugs or fireflies catching lightning are actually neither bugs nor flies. A truer term for them bugs may occupy might be “lantern beetles.” Their young, sometimes the nostalgic called glowworms, should really be called “glow larvae.” pinnacle—even All fireflies belong to the family of beetles known above chasing the as Lampyridae, from the Greek word for “shining.” ice cream truck Lampyrids encompass 110 genera and thousands of and running through the sprinkler. Fireflies turn an species worldwide. In West Virginia, we have at least Wordinary backyard into a fairyland. On the stillest, most six genera and 13 species—that’s what’s represented so satisfying evenings, when the grass is mown and the far in the state Department of Agriculture’s quarter- bicycles have been put away or when the tent has been million-specimen insect collection in Charleston, pitched and the marshmallows are melding the s’mores, according to Taxonomic Entomologist and collection even adults can be caught in their spell. Curator Laura Miller. “There could be more,” she says. Lightning bugs hold such a place of enchantment Fireflies are masters of biochemistry. Like many in our hearts that we don’t think of them as having other creatures that glow, they make their light by a normal insect role in lawn and garden ecology. But combining a compound called a luciferin with the “they’re highly beneficial, especially if you have slug or enzyme luciferase—both named from Latin “lux,” for snail problems,” says Daniel Frank, an entomologist “light.” “When luciferin and luciferase come together with the West Virginia University Extension Service. in the presence of oxygen, they make a flash,” Frank That is, these creatures of magic are also predators. says. It’s one kind of bioluminescence. “Some call it a “The larval stage feeds on various invertebrates in and ‘cold light’ because it really doesn’t release heat like an on the soil—that includes snails and slugs—and they incandescent bulb does,” he says. “It’s pretty much 100 can attack other pest insects, too.” percent efficient.” Like a lot of us, though, lightning bugs lavish their If you’ve never seen a glowworm, they’re not too most spectacular behaviors on courtship. What for us is hard to find once you know the firefly life cycle. Like all a charming phase of the warmer months is, for lightning beetles, fireflies go through a complete metamorphosis,

bugs, mating season. with a cycle of four stages: egg, larva, pupa, adult. TESSA NICKELS

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Fireflies emerge at dusk in a quiet Logan County field.

”THESE GRACEFUL INSECTS ARE TRULY MIRACULOUS BECAUSE THEY SO BEAUTIFULLY ILLUMINATE THE CREATIVE IMPROVISATION OF EVOLUTION. THEY’VE BEEN SHAPED BY TWO POWERFUL EVOLUTIONARY FORCES: NATURAL SELECTION, THE STRUGGLE FOR SURVIVAL, AND SEXUAL SELECTION, THE STRUGGLE FOR REPRODUCTIVE OPPORTUNITY.” Sara Lewis, Tufts University professor of evolutionary and behavioral ecology

Females lay their eggs in places where the soil is moist, and perched on vegetation, respond with single flashes. eggs take a few weeks to hatch. “They generally live for Males approach females, and consummation ensues. about a year, in most species. They spend the immature, Even the broadest lines of that interaction—males larval stage overwintering in the soil,” Frank says. These are in the air, females stationary—are lost on us humans. the glowworms. In fall and spring, they can sometimes be Yet there’s so much more nuance to it than that—for found glowing at the soil under leaf litter, where they hunt example, color. That’s how taxonomist Miller organizes small prey. lightning bugs for people who aren’t insect scientists. After the winter, “they pupate in the soil and then emerge “I have listed them by their light-producing colors,” as adults, usually in late spring or early summer,” Frank says. she writes in an email detailing her West Virginia “If we have a really warm spring, you’d see emergence earlier. collection’s Lampyrids. Their luminescences fall into Then they’ll typically be out and about until around July—or, three main color categories. if we have moist, humid weather all summer, that could Most of the firefly lanterns we see give off the expand how late we see them, maybe even into the fall.” familiar light yellow-to-green glow. That’s usually By “out and about,” he means advertising for love. Photinus pyralis, the Common Eastern Firefly that’s pretty ubiquitous across the eastern U.S. It could also be Love Languages its close relatives, four or more other species of Photinus The typical lightning bug courtship goes like this: that live here in the state. They’re the iconic half-inch-

TESSA NICKELS Males fly around, flashing ardently. Interested females, or-so-long lightning bug.

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Look closer: Do you notice an amber tint? That’s not necessarily a mutant. It could be one of West Virginia’s Pyractomena species. Also about a half-inch long but darker-winged, they’re found in wetter areas and their larvae feed on aquatic snails. Or is your flasher more of a dark green? That could be the cannibalistic Photuris— more on that below. They range larger, from half an inch to almost an inch in length. Timing, in Romance, is Everything But lantern color isn’t the only way to distinguish one type of lightning bug from another. “Species can also be separated or identified in the field by the number, duration, and frequency of their flashes,” Miller says. The differences can be minute, but some flash patterns are easy to pick out. The common Photinus pyralis is fairly easily identified by its distinctive J-shaped flash pattern. The malePhotinus consanguineus has been documented with a double flash. If you see rapid flashes—four or more in the space of a second—you’re probably looking at Pyractomena angulata or Pyractomena dispersa. By having a unique flash pattern, each species can find its proper mate in the low light of dusk. Seeking intimacy in the dark can be dangerous, though. The female Photuris, the cannibal mentioned above, mimics the flash response a hovering male Photinus is looking for. When he lands, she injects him with her digestive venom and eats him. This Point Photuris isn’t looking for love. She’s after defensive Pleasant-area compounds in Photinus’s blood that make it unpalatable wetland is a popular to spiders and other predators. Photuris acquires the rendezvous protection for herself and also passes it on to her eggs. spot for the The Photuris female is, in the words of Tufts University old-fashioned fun of catching biologist Sara Lewis, “a firefly vampire brought to you lightning bugs. by natural selection.” NICKELS TESSA THORNTON; JESSE

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Documenting and Protecting incomplete—entomologists see several possible causes. Lightning bugs Firefly behaviors beyond outrageous conduct haven’t been “Habitat loss will cause problems,” Frank says. “If even live at the top of Spruce thoroughly documented. While they can vary a lot—the you’re covering land with concrete or converting land Knob, the insects flash more slowly at higher temperatures, for example, to industrial agriculture, that takes away habitat they highest point and they may be affected by wind speed or pollution or factors would use—they like wooded areas and fencerows. And in the state. we’re not even aware of—harmless insects don’t attract the if you’re disturbing the soil, you don’t have that habitat level of scientific resources the pests we need to control do. the larvae need to survive.” Pesticides and artificial But some firefly behaviors are perfect subjects for citizen- light may contribute, too. “Light pollution has become scientist observations, along the lines of Audubon Society a problem for a number of insects,” Frank says. Simple bird counts. Firefly Watch, an online project of the Boston steps like reducing the amount of light we use outside Museum of Science, has logged data from thousands of our houses in the evening and avoiding harsh lawn and observers across North America since 2008. In West Virginia, garden chemicals may help. participants have noted single, double, triple, quadruple, and Do we really need fireflies? Biologist Lewis asked flickering flash patterns as early as April 25 and as late as and answered this question in “The Loves and Lies of October 9, under very specifically documented conditions of Fireflies,” her popular TED talk: “Every time a species habitat and weather. is lost, it’s like extinguishing a room full of candles one Some ecologists believe there’s been a decline in the by one,” she said. “You might not notice when the first numbers of lightning bugs in recent decades. If that’s few flames flicker out—but in the end, you’re left sitting true—it’s hard to be sure because documentation is so in darkness.”

OBSERVING FIREFLIES

Wear bug spray and be alert Shine a blue light. Flashlights Handle fireflies gently. Don’t Start a notebook. Record any for ticks. If you’re looking in tall disrupt firefly communication, handle a firefly if you have insect field observations you make. You grass near wooded areas, tuck but the insects can’t see blue repellant on your hands—if might be amazed how much you your pant legs into your socks light. Tape a piece of blue possible, use a net. If you put notice when you begin to write and your shirt into your pants. acetate over your flashlight— them in a jar, add a piece of down what you see. Check yourself carefully after. you can find it at most art moist paper towel to keep the supply stores. jar humid. Let them go as soon

MATT DIETERICH as you’ve had a good look. Source: mos.org/fireflywatch

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